Increased FAME (BioDiesel) content in gas oil, a major cause of concern

Increased FAME (BioDiesel) content in gas oil, a major cause of concern

Posted by
Increased FAME (BioDiesel) content in gas oil, a major cause of concern

Business owners and farmers worried about its impact on their machinery

Increase in FAME (Biodiesel) element of Sulphur Free Gas Oil (SFGO) has led to widespread concern especially amongst business owners and farmers who use off-road or mobile machinery. There have been reports of clogged filters and low fuel pressure recently due to these changes in fuel specifications and the very nature of FAME (Biodiesel).

Story so far

SFGO is an eco-friendly gas oil with a sulphur level of 10 parts per million that is used for Non-Road Mobile Machinery (NRMM), such as tractors, forklift trucks, excavators, quarrying equipment, etc… UK road fuel has had FAME of up to 7% since 2004 but it has never been blended into non-road fuel due to cost. Then the British Standard for non-road diesel was revised in 2006 to allow for the addition of FAME to SFGO. But it was never really a concern until 2008 when the Renewable Transport Fuel Obligation (RTFO) started setting volume targets for renewable fuels in UK to reduce CO2 emissions. The percentage of fuels derived from renewable sources was at 7.25% in April 2018 and 8.50% in January 2019. It is expected to increase to 12.40% by 2032. In order to meet the targets, set by RTFO, manufacturers started adding FAME to SFGO which in turn caused issues to storage tanks and other related equipment. So, it’s important to understand the impact of FAME (Biodiesel) on tanks and equipment and act accordingly.

What is FAME (Biodiesel)?
Biodiesel is manufactured from used cooking oil, waste fat, animal fat, plant oil and other plant-based material. The biodiesel manufacturing process converts these oils and fats into molecules which are referred to as Fatty Acid Methyl Esters (FAME). While biodiesel produced from used cooking oil or other waste fat could reduce CO2 emissions by as much as 85%, it has a lot of problems as well.

Problems with FAME

Since FAME is a powerful solvent and is hygroscopic (attracts and holds on to water) it can cause the following problems:

  • Material incompatibility – Rubbers, plastics, and surface coatings will degrade when they are in contact with FAME.
  • Clogged Filters – The residual deposits can cause the water particulate filters in the tank to get clogged.
  • Water Contamination – Owing to the hygroscopic nature of FAME, it is more likely to hold on to water, which can cause growth of microbes / bacteria / bugs in the fuel.
  • Degradation of Fuel – Oxidation and hydrolysis can cause the gradual degradation of fuel which can damage the machinery.
  • Cold flow premature waxing and precipitation problems

How to get prepared?

Here are a few best practices to minimise the harmful effects of FAME (Biodiesel):

  • Keep the tank clean – Make sure that your tank is professionally cleaned each time you take delivery of FAME (Biodiesel). It is important to remove water, solid deposits or mould growth before filling the tank with FAME (Biodiesel). If you are not able to clean the tank professionally, make sure that you thoroughly check the condition of your tank and fix any issues immediately.
  • Check tank for bacteria – Since there is an increased risk of bacterial growth, it is important to do regular tank checks to ensure that there is no growth of bacteria in the tank. If there is a bacterial growth, it can be solved either by emptying and cleaning the tanks. You can even use additives and filters to prevent the growth of bacteria in the long term.
  • Check tank for degradation – Make sure you check the tank regularly for any degradation in structure, material of the tank or any surface coatings used.
  • Check for cracks and leaks – This is particularly relevant for older fuel storage tanks. Check the tank for any signs of leakage or damage and get it fixed.
  • Check the particulate and water filters – There is an increased possibility that the addition of FAME will cause premature blocking of filters from time to time on dispensing tanks especially during the winter. Therefore, it is good practice to regularly change any filters.
  • Check all components – Make sure that the pipework, seals, pumps and other components are checked regularly. And, if there are any leaks, get it fixed immediately.
  • Prevent water ingress – Water is the biggest threat to FAME (Biodiesel) as it is hygroscopic. Make sure your tank is protected against water ingress caused by rain. So, water needs to be drained off regularly. Once water is in the fuel, it can cause corrosion of equipment and allow growth of bacteria. You can even use a water identifying paste to check if there is water content in the fuel.
  • Ensure there is no moisture – Make sure your tank is brimful ensuring that there is very little air in the tank which can potentially cause moisture. Ensure that the bottom of the tank is drained of water. It’s a good practice to install appropriate breathers to keep ambient humidity out or arrange for a steady stream of dry air to be fed across the space on top of the tank.
  • Avoid storage of FAME (Biodiesel) for long periods – Ideally, FAME (Biodiesel) should not be stored for more than 6 months as it has limited shelf life.
  • Use of additives – You can use additives to bring your fuel up to performance specifications. Its best to get a trained professional to do this for you.
  • Buy fuel from a reputed distributor – It is always good practice to purchase fuel from a reputed distributor who is certified to meet all local standards.

If you are a business owner or a farmer using Harlequin fuel storage tank to store FAME (Biodiesel) and need more advice on how to tackle this problem, do get in touch with our team on 028 9261 1077 or send an email to

More information here.

Sources of Information: